Tape heating methods

ABSTRACT

Implementations of a method of increasing the adhesion of a tape. Implementations may include: mounting a tape to a frame, mounting a substrate to the tape, heating the tape after mounting the substrate at one or more temperatures for a predetermined period of time, and increasing an adhesion of the tape to the substrate through heating the tape.

BACKGROUND Technical Field

Aspects of this document relate generally to semiconductor substrates,such as substrates used for semiconductor device fabrication.

2. Background

Semiconductor devices are formed on semiconductor substrates. Thesemiconductor devices may be formed in or on the substrates usingvarious fabrication techniques including photolithography, deposition,implantation, and etching. Following fabrication, the semiconductordevices formed on the substrate need to be separated from each otherusing a singulation process into a plurality of semiconductor die.

SUMMARY

Implementations of a method of increasing the adhesion of a tape mayinclude: mounting a tape to a frame, mounting a substrate to the tape,heating the tape after mounting the substrate at one or moretemperatures for a predetermined period of time, and increasing anadhesion of the tape to the substrate through heating the tape.

Implementations of a method of increasing the adhesion of a tape mayinclude one, all, or any of the following:

The method may further include at least partially singulating thesubstrate on the tape after mounting and flipping the at least partiallysingulated substrate onto a second tape before heating the tape.

The one or more temperatures may be a temperature ramp up, a temperatureramp down, or any combination thereof during the predetermined period oftime.

The one or more temperatures may be a single temperature during thepredetermined period of time.

Heating the tape may further include heating using a heating chuck.

Heating the tape may further include heating using two or more heatingchucks.

The one or more temperatures may be less than 100 C.

Implementations of a method of increasing an adhesion of a tape mayinclude mounting a semiconductor substrate to a tape, heating the tapeafter mounting the semiconductor substrate at one or more temperaturesless than 100 C for a predetermined period of time, and increasing anadhesion of the tape to the semiconductor substrate through heating thetape.

Implementations of a method of increasing an adhesion of a tape mayinclude one, all, or any of the following:

The method may include at least partially singulating the substrate onthe tape after mounting and flipping the at least partially singulatedsubstrate onto a second tape before heating the tape.

The one or more temperatures may be a temperature ramp up, a temperatureramp down, or any combination thereof during the predetermined period oftime.

The one or more temperatures may be a single temperature during thepredetermined period of time.

Heating the tape may further include heating using a heating chuck.

Heating the tape may further include heating using two or more heatingchucks.

Implementations of a method of preventing die loss from a tape mayinclude mounting a semiconductor substrate to a tape and heating thetape after mounting the semiconductor substrate at one or moretemperature for a predetermined period of time. The method may includeat least partially singulating a plurality of die from the semiconductorsubstrate and preventing die from decoupling from the tape duringsubsequent processing operations by increasing an adhesion of theplurality of die to the tape through heating the tape.

Implementations of a method of preventing die loss from a tape mayinclude one all, or any of the following:

The one or more temperatures may be a single temperature during thepredetermined period of time.

At least partially singulating the substrate on the tape may occurbefore heating the tape and the method may further include flipping theat least partially singulated substrate onto a second tape beforeheating the tape.

The one or more temperatures may be a temperature ramp up, a temperatureramp down, or any combination thereof during the predetermined period oftime. Heating the tape may further include heating using a heatingchuck.

Heating the tape may further include heating using two or more heatingchucks.

The one or more temperatures may be less than 100 C.

The foregoing and other aspects, features, and advantages will beapparent to those artisans of ordinary skill in the art from theDESCRIPTION and DRAWINGS, and from the CLAIMS.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations will hereinafter be described in conjunction with theappended drawings, where like designations denote like elements, and:

FIG. 1 is a side view of a plurality of semiconductor die mounted to atape mounted to a frame;

FIG. 2 is a side view of the plurality of semiconductor die of FIG. 1during a jet ablation process;

FIG. 3 is side view of a plurality of semiconductor die mounted to atape mounted to a frame placed over a heating chuck during heating ofthe tape;

FIG. 4 a side view of the plurality of semiconductor die of FIG. 3during a jet ablation process.

DESCRIPTION

This disclosure, its aspects and implementations, are not limited to thespecific components, assembly procedures or method elements disclosedherein. Many additional components, assembly procedures and/or methodelements known in the art consistent with the intended tape heatingmethods will become apparent for use with particular implementationsfrom this disclosure. Accordingly, for example, although particularimplementations are disclosed, such implementations and implementingcomponents may comprise any shape, size, style, type, model, version,measurement, concentration, material, quantity, method element, step,and/or the like as is known in the art for such tape heating methods,and implementing components and methods, consistent with the intendedoperation and methods.

Many different semiconductor substrates have been devised to enable theformation of many different kinds of semiconductor substrates. Othersubstrate types are often used to form various parts of semiconductorpackages or other assemblies where precisely cut parts are needed (imagesensor lids, metal structures for packaging substrates, etc.).Singulation techniques and methods for use with various semiconductorsubstrates and other substrates are disclosed in this document. Examplesof semiconductor substrates that may be used include, by non-limitingexample, single crystal silicon, polysilicon, amorphous silicon, glass,sapphire, ruby, gallium arsenide, silicon carbide, silicon-on-insulator,and any other semiconductor substrate type. Examples of other substratesthat may be used in various implementations may include, by non-limitingexample, glass, metals, metal alloys, laminated materials, ceramicmaterials, and any other planar material capable of being singulatedusing a singulation process. Where the substrate is a semiconductorsubstrate, the substrate is singulated to produce a plurality ofsemiconductor die (die). Where the substrate is another type ofsubstrate, the substrate is singulated to produce a component, such as,by non-limiting example, image sensor lids, metal backplanes, metalportions for use in laminated or sintered packaging substrates, heatsinks, or any other precisely cut component from a sheet of material.

Referring to FIG. 1, a plurality of die 2 are illustrated coupled with atape 4 mounted to frame 6. The plurality of die 2 have been singulatedfrom a semiconductor substrate that was previously mounted to the tapeeither simultaneously as the tape was mounted to the frame or prior tothe time the tape was mounted to the frame. The tape used may be any ofa wide variety of tape types, including, by non-limiting example, dicingtape, backgrinding tape, ultraviolet (UV), UV release tape, releasetapes, or any other tape type capable of coupling with the substrate. Ithas been observed that many tapes exhibit the behavior that the adhesiveforce between the tape and the substrate/die coupled with the tapechanges over time. For many tapes, the adhesive force increases overtime and becomes noticeable after a period of weeks or months followingadhesion of the substrate/die to the tape. Because of this, ifsufficient time passes, it can become difficult to use ordinaryprocesses to remove singulated die or cut parts from the tape becausethe adhesive force has become too strong. This has the effect oflimiting the amount of time the die or cut parts can be stored while onthe tape. The problems observed while removing die from tape where theadhesive force has increased beyond usually observed levels include nothaving sufficient force or suction from the die picking tool to remove adie from the tape, residual adhesive on the back of the die followingremoval, or breakage of the die as it is lifted from the tape. Where thedie are thin die (less than 75 microns thick), variations in theadhesive force between the tape and the die may significantly affectyield.

In other process steps during or following singulation of the substrateinto die or cut parts, having sufficient adhesive force between thedie/substrate and the tape is important. For example, where jet ablationis used to singulate the substrate into die/cut parts, if insufficientadhesive force exists between the tape and the die/substrate, thedie/cut parts ultimately wash off/fall off the tape and are lost. Whereplasma singulation of the die is employed and a UV cure/release tape isused, during jet ablation and/or solvent cleaning steps following plasmasingulation the die need to have sufficient adhesive force to preventcoming off of the tape before the tape is UV cured to reduce theadhesive force of the tape and allow the die to be picked from the tape.FIG. 2 illustrates what happens during a jet ablation process 12 of thedie in FIG. 1 where the adhesive force between the die 2 and the tape 4is marginal. As illustrated, some of the die 2 originally present inFIG. 1 have been entirely washed away from the tape. One of the die 8 ispartially lifted from the tape 4 and could fall off during handling orsubsequent picking processes. Another die 10 has been chipped by the diewashing off of the tape 4. All of these conditions directly impact theyield of the process.

With all tapes, there are normal observed variations in the adhesiveforce between the tape and the substrate, both across the surface of agiven tape and between rolls/lots of the same tape. The variation occursin part because of differences in the thickness of the adhesive appliedto the tape, variations in the thickness of the tape itself, or how longit has been since the tape was manufactured. All of these variationsreduce the process window for any die singulation and picking process.For example, for a plasma die singulation process, the maximum allowablepressure at which the solvent cleaning and/or jet ablation process canoperated has to be reduced to the level where the process will not peelthe die/parts away if tape having the lowest known naturally varyingadhesive force is being processed. This can affect the effectiveness ofthe other processes as if the maximum allowable pressure is too low,then the back metal of the die may not be able to be singulated usingjet ablation or the die may not be sufficient cleaned during solventcleaning. This narrow process window may prevent back metal thicknessesabove certain values from being able to be jet ablated.

The various methods of heating tapes disclosed in this document mayoperate to increase the singulation process window(s) through reducingthe observed variation in adhesive force of the tapes and/or stabilizingthe adhesive force of the tapes so that the force does not changesignificantly or substantially over a period of weeks and months.Referring to FIG. 3, a plurality of die 14 are illustrated coupled to atape 16 supported by a frame 18. As illustrated, the tape 16 has beenplaced over a heating chuck 20 and heat is being applied to the tape 16.During application of the heat, the uniformity of the adhesion of thetape to the die 14 may increase and the overall adhesive force betweenthe tape 16 and the die 14 increases when compared with the adhesiveforce when the die were originally coupled to the tape 16. An additionaleffect to heating the tape is to substantially reduce the rate at whichthe adhesive force between the die 14 and the tape 16 increase over timeor to substantially stop any increase in adhesive force over time(freeze the adhesive force going forward at a particular value).

As illustrated in FIG. 3, the tape 16 is being heated after the die 14have been singulated or substantially singulated. However, in otherimplementations, the tape 16 may be heated before any singulation hasbegun after the substrate has been mounted to the tape. In someimplementations, the tape 16 may be heated prior to the substrate beingmounted to the tape. In these implementations, the tape 16 may be heatedafter the tape has been mounted to the frame but before the substrate ismounted to the tape. As an example of a possible process singulationprocess implementation, the substrate/plurality of die are first mountedto a first tape, and then the substrate/plurality of die are at leastpartially singulated using any of a wide variety of processes (sawing,plasma etching, laser scribing). The first tape is then exposed to UVlight to release the at least partially singulated substrates/pluralityof die. The at least partially singulated substrates/plurality of dieare then demounted/flipped onto a second tape and the first tape isremoved. The second tape is then heated using any of the various methoddisclosed in this document. Following heating of the tape, the at leastpartially singulated substrates/plurality of die may then be jet ablatedto remove any residual material between the at least partiallysingulated substrates/plurality of die. Following the jet ablationprocess, the second tape is then exposed to UV light to reduce theadhesive force of the second tape on the at least partially singulatedsubstrates/plurality of die. The now fully singulatedsubstrates/plurality of die can then be demounted/flipped onto a thirdtape (picking tape) and then shipped for further processing in anassembly process where the singulated substrates or plurality of die areused in semiconductor packaging or other operations. In variousimplementations, the third tape may not be used and the second tape maybe shipped for further processing in the assembly process (used as apicking tape).

A wide variety of systems may be used to apply heat to the tape 16 invarious implementations. In some, the tape 16 may be heated using aheating chuck 20 as illustrated in FIG. 3. In these implementations, theheating chuck 20 may be maintained at a single temperature the entiretime the tape 16 is in contact with the heating chuck 20, or thetemperature of the heating chuck may be ramped up from an initialtemperature to a higher final temperature during the period of time thetape 16 contacts the chuck 20. In various implementations, thetemperature of the heating chuck may be ramped down from an initialtemperature to a lower final temperature during the period of time thetape 16 contacts the chuck 20. In other implementations, the temperaturemay ramp up from an initial temperature to a higher intermediatetemperature, then ramp down from the intermediate temperature to a lowerfinal temperature which may be the same as the initial temperature ormay be a different temperature. Multiple cycles of temperature rampingup and ramping down may be employed in various implementations as well.In various implementations, one chuck may be used to heat the tape 16;in others, two or more heating chucks could be used. In implementationswhere two or more heating chucks are used, each chuck may be at the sametemperature or different temperatures and each chuck could maintain atemperature or perform one or more temperature ramp up or ramp downcycles while the tape is in contact with each chuck. A wide variety ofheating possibilities are possible where heating chucks are used.

In various implementations, a heating chuck may not be used, and insteada heating chamber may be employed to heat the substrate/plurality of diecoupled to the tape (or the tape itself mounted to a frame, depending onthe implementation). The heating chamber encloses the entire surface ofthe tape and may or may not fully enclose the structure of the framedepending on the chamber design. A single frame with tape may beprocessed in certain heating chamber implementations, or multiple frameswith tape may be processed in other heating chamber implementations.Where a heating chamber is employed, a heated fluid is used to transferheat to the tape. In various implementations, the fluid may be a gas orliquid, such as, by non-limiting example, air, nitrogen, clean dry air,water, glycol, or any other fluid type. While the tape is beingprocessed in the heating chamber, the chamber may be temperaturecontrolled in any manner previously described for the heatingchuck(s)—single temperature, temperature ramp up, temperature ramp down,multiple substantially fixed temperature periods (stepped temperatures),and any combination thereof. Multiple heating chambers may also beemployed to help apply the heat to the tape according to the desiredtemperature profile, where the frame with the tape is moved from onechamber to another.

In various implementations, the temperature may be a lower temperatureprocess where the temperature(s) used while heating the tape are lessthan 100 C and higher than ambient temperature. In particularimplementations, the temperature may be a single temperature of 80 C. Awide variety of temperatures in this range, including temperature rampsand stepped temperature profiles may be employed in various methodimplementations. The period of time the tape 16 is heated may also bevaried. The period of time used may depend on the type of tape, thedegree of final adhesive force desired at the end of processing, thesubstrate/die type, or any other factor affecting the adhesive force ofthe tape. For example, some tapes may generate sufficient adhesive forceafter exposure to 60 C temperature for 15 minutes. In particularimplementations, the period of time may be 90 minutes. A wide variety oftemperature(s) and heating times may be employed in variousimplementations in view of the tape type, substrate type, and any otherfactor disclosed herein that affects the adhesive force (adhesion) ofthe tape.

In the various method implementations disclosed in this document, whereUV cure/release tapes are employed, the heating of the tape may becalculated to produce a desired adhesive force after the tape has beenexposed to UV light. In such implementations, the method includes the UVlight exposure process including the particular wavelength(s) andexposure times that act to cause the adhesive of the tape to chemicallychange under the influence of the UV light. The particulartemperature(s) and heat application times may be varied depending on thecharacteristics of the UV tape to allow the tape to provide the desiredadhesive force both prior to and after UV exposure.

Referring to FIG. 4, the plurality of die 14 of FIG. 3 are illustratedafter the tape 16 has been heated by the chuck 20. As is illustrated, ajet ablation process 22 is currently being used to wash/complete thesingulation process for the plurality of die 14. Because the adhesiveforce of the tape 16 has been increased to the desired level uniformlyacross the surface of the tape 16, none of the die 14 have decoupledfrom the tape or partially come off. Accordingly, the heating of thetape has helped assist with preventing yield loss at the jet ablationprocess 22 step because of inadequate adhesive force between the tape 16and the die 14. The die 14 can now be picked from the tape 16 and movedon to subsequent packaging operations to form semiconductor packageswith the die 14.

In places where the description above refers to particularimplementations of tape heating methods and implementing components,sub-components, methods and sub-methods, it should be readily apparentthat a number of modifications may be made without departing from thespirit thereof and that these implementations, implementing components,sub-components, methods and sub-methods may be applied to other tapeheating methods.

1. A method of increasing an adhesion of a dicing tape, the methodcomprising: mounting the dicing tape to a frame; mounting a substrate tothe dicing tape after the dicing tape is mounted to the frame; heatingthe dicing tape after mounting the substrate at one or more temperaturesfor a predetermined period of time; increasing an adhesion of the dicingtape to the substrate through heating the dicing tape; and removing oneor more portions of the substrate through releasing the dicing tape fromthe one or more portions.
 2. The method of claim 1, further comprisingat least partially singulating the substrate on the dicing tape aftermounting and flipping the at least partially singulated substrate onto asecond tape before heating the dicing tape.
 3. The method of claim 1,wherein the one or more temperatures is one of a temperature ramp up, atemperature ramp down, or any combination thereof during thepredetermined period of time.
 4. The method of claim 1, wherein the oneor more temperatures is a single temperature during the predeterminedperiod of time.
 5. The method of claim 1, wherein heating the dicingtape further comprises heating using a heating chuck.
 6. The method ofclaim 1, wherein heating the dicing tape further comprises heating usingtwo or more heating chucks.
 7. The method of claim 1, wherein the one ormore temperatures are less than 100 C.
 8. A method of increasing anadhesion of a dicing tape, the method comprising: mounting asemiconductor substrate to the dicing tape after mounting the dicingtape to a frame; heating the dicing tape after mounting thesemiconductor substrate at one or more temperatures less than 100 C fora predetermined period of time; and increasing an adhesion of the dicingtape to the semiconductor substrate through heating the dicing tape;removing one or more portions of the substrate through releasing thedicing tape from the one or more portions.
 9. The method of claim 8,further comprising at least partially singulating the substrate on thedicing tape after mounting and flipping the at least partiallysingulated substrate onto a second tape before heating the dicing tape.10. The method of claim 8, wherein the one or more temperatures is oneof a temperature ramp up, a temperature ramp down, or any combinationthereof during the predetermined period of time.
 11. The method of claim8, wherein the one or more temperatures is a single temperature duringthe predetermined period of time.
 12. The method of claim 8, whereinheating the dicing tape further comprises heating using a heating chuck.13. The method of claim 8, wherein heating the dicing tape furthercomprises heating using two or more heating chucks.
 14. A method ofpreventing die loss from a dicing tape, the method comprising: mountinga semiconductor substrate to the dicing tape; heating the tape aftermounting the semiconductor substrate at one or more temperatures for apredetermined period of time; at least partially singulating a pluralityof die from the semiconductor substrate before heating the tape; andpreventing die from prematurely decoupling from the dicing tape duringsubsequent processing operations by increasing an adhesion of theplurality of die to the dicing tape through heating the dicing tape;removing one or more portions of the substrate through releasing thedicing tape from the one or more portions.
 15. The method of claim 14,wherein the one or more temperatures is a single temperature during thepredetermined period of time.
 16. The method of claim 14, furthercomprising flipping the at least partially singulated substrate onto asecond tape before heating the tape.
 17. The method of claim 14, whereinthe one or more temperatures is one of a temperature ramp up, atemperature ramp down, or any combination thereof during thepredetermined period of time.
 18. The method of claim 14, whereinheating the dicing tape further comprises heating using a heating chuck.19. The method of claim 14, wherein heating the dicing tape furthercomprises heating using two or more heating chucks.
 20. The method ofclaim 14, wherein the one or more temperatures are less than 100 C.